I'm new to RR'ing and am planning a G scale layout in my basement to be a shelf mount next to the ceiling. The room is 42" x 12'. One of the 42' walls is not where I want a train track so I'm thinking about using the same track on the other 42' wall for running the train in both directions. That means I need some type of switch to make a loop back. Are there automatic switches to do this or any other type of switch that you would recommend? Thanks, Jim

I'm getting really good information that is helping me a lot. Thanks everyone. I can see its easy to make new RR friends.

I have spent many hours on the Internet reading blogs and I have enough information to now be thoroughly confused.  I'm new to railroading and want to set up a G train & track in my basement. I plan to put a 6" shelf close to the ceiling and it will only be a simple loop with no intersections.  From my reading I understand that I must use at least a 4'Radius corner to handle diesels locomotives and look realistic. My room is 42' x 12' and I plan two 4'R corners  on the one end, and the other end will be a 6'R ½ circle.
My questions:
1. Is my understanding so far correct? Is a 6" shelf the minimum size I can put up?
2. Since its indoors, should I use steel or brass. Brass is much cheaper but I heard it requires a lot of cleaning? What do you suggest for indoors?
3. I don't want to get into bending flex track, so can I buy 4'R & 6'Radius corners pre made in both brass and steel?
Any other suggestions to this new railroad modeler will be greatly appreciated.
Jim